Should I switch boosters? Parkway --> ?

[3isEnough]

We currently have a Parkway SGL for my 8.5yo (53lbs, 52").

I need to purchase a LBB for him and friends to use on occasion and I've settled on the Clek Olli.

However, before pulling the trigger on the Clek I wanted to ask about the Parkway. My DS often falls asleep in the Parkway on long drives and nearly falls out of it, head slumped forward, body twisted, seatbelt pressing against neck, etc. So I'm wondering if I should just convert my current Parkway into the LBB (and not buy the Clek) and instead buy a different HBB for my DS.

Is there another HBB that might be more suitable for an 8.5yo for sleeping on long drives? I suppose I could get him a Radian or Frontier and use it in harness mode since he won't be 80/85lbs for a long time, but he will likely resist going back into a 5pt harness.

Any recommendations to make him safer on long drives? TIA!

[Joolsplus2]

Do your vehicle seats recline any? Maybe clicking them back a notch would help your uber-relaxed kiddo stay more upright? The Monterey is also a nice choice, I've never heard of kids flopping out of that (never heard of them flopping out of the PW either, so yikes, not sure what to predict!), or the Safety 1st Air Protect (though I've loaned mine to a kid who's kind of too young and Ive been terrified to ask his mother if he flops out of it when he sleeps).

My kids never liked the Clek, it's too short for ample leg support and they ended up with their knees in their faces and their feet on the front edge of the vehicle seat for comfort (a small light plastic footrest or the large free priority mailing box are also good for foot support, as eventually all kids need something, in any booster...hmmm...maybe it would help in the PW for sleeping, even? That would be cheap to try!). Big Kid Amp or Harmony Cruz are nice, or yeah to the backless parkway and a Monterey or whatever for a new highback.

[3isEnough]

Do your vehicle seats recline any? Maybe clicking them back a notch would help your uber-relaxed kiddo stay more upright? The Monterey is also a nice choice, I've never heard of kids flopping out of that (never heard of them flopping out of the PW either, so yikes, not sure what to predict!), or the Safety 1st Air Protect (though I've loaned mine to a kid who's kind of too young and Ive been terrified to ask his mother if he flops out of it when he sleeps).

Thanks so much for your response Jools! I never considered reclining the seat back a bit, that's a great idea and I'll try it today. That little bit could help him stay back instead of slumping forward when he sleeps. He's a really heavy sleeper both at home and in the car, so his body just goes where gravity takes it in the PW and he just keeps on sleeping.

I appreciate the other recs, I'll check those out online today and figure out where to go from here. I'm about to buy 2 Frontiers to replace my other DS' seats that are expiring so I'm trying to sort it all out at once.